$("body * :first-child").addClass('first-child');
$("body * :nth-child(2)").addClass('nth-child2');
$("body * :nth-child(3)").addClass('nth-child3');
$("body * :nth-child(4)").addClass('nth-child4');
$("body * :nth-child(5)").addClass('nth-child5');
$("body * :nth-child(6)").addClass('nth-child6');
$("body * :nth-child(7)").addClass('nth-child7');
$("body * :last-child").addClass('last-child');